Ivan Kalik wrote:
The phones need to be in a tagged vlan instead of an untagged.
Are you sure about that? You tag VLANs on a trunk port. And that port will be connected to the upstream device, not your phone.
No, it's quite common for VoIP hardphones to have a passthrough port - effectively a 3-port switch - one facing the network, one facing the desktop PC, and one facing the phones internals. It's quite common to be able to put the phone on the tagged vlan and the PC on the untagged. It's less often useful IMHO, but "Cisco say so" is often the reason ;o) For interest: obviously the phone needs to know the tag number. LLDP-MED is the "normal" way of signalling this, or CDP on all-Cisco networks. Responding to the OP, whether you can do this and the syntax to use depends on your switch. For example with 3Com 4400 and (I think) Extreme x450 you do this: Tunnel-Type = VLAN, Tunnel-Medium-Type = IEEE-802, Tunnel-Private-Group-id = "20 30t" ...to put vlan 20 untagged and 30 tagged. Some switch vendors may require a VSA to put a tagged vlan. What model switch are you using?